U.S. patent application number 10/075675 was filed with the patent office on 2003-08-21 for transcranial electrostimulation apparatus and method.
Invention is credited to Katsnelson, Yakov S..
Application Number | 20030158589 10/075675 |
Document ID | / |
Family ID | 34229319 |
Filed Date | 2003-08-21 |
United States Patent
Application |
20030158589 |
Kind Code |
A1 |
Katsnelson, Yakov S. |
August 21, 2003 |
Transcranial electrostimulation apparatus and method
Abstract
Transcranial electrostimulation apparatus and method includes a
first generator of bipolar pulses of a first predetermined
frequency. A source of modulating control signals, producing an
output at a second frequency less than the first predetermined
frequency, is used to cause the output pulses from the first
generator of pulses to vary in amplitude in a predetermined
asymmetrical pattern at the frequency of the modulating control
signals, with the asymmetrical pattern of signals applied to output
electrodes designed to be attached to the scalp of a patient.
Inventors: |
Katsnelson, Yakov S.;
(Bronx, NY) |
Correspondence
Address: |
LaValle D. Ptak
Ste. B
28435 N. 42nd St.
Cave Creek
AZ
85331
US
|
Family ID: |
34229319 |
Appl. No.: |
10/075675 |
Filed: |
February 15, 2002 |
Current U.S.
Class: |
607/72 ;
607/68 |
Current CPC
Class: |
A61N 1/36021 20130101;
A61N 1/32 20130101 |
Class at
Publication: |
607/72 ;
607/68 |
International
Class: |
A61N 001/18 |
Claims
What is claimed is:
1. A method for effecting transcranial electrostimulation including
the steps of: producing an asymmetrical tone burst envelope
comprising a predetermined number of squarewave pulses, a first
portion of which constitutes a high amplitude burst followed by a
second portion which constitutes a low amplitude burst; repeating
the asymmetrical tone burst successively at a repetition frequency
that is between 70 Hertz and 85 Hertz; and delivering the repeated
tone burst signals to electrodes of a transcranial
electrostimulation apparatus.
2. The method according to claim 1 wherein the frequency of pulses
comprising the asymmetrical tone burst is approximately 1150 to
1450 times the repetition frequency.
3. The method according to claim 1 wherein the duration of the high
amplitude first portion of each tone burst is substantially
twenty-five percent of the total duration of the tone burst.
4. The method according to claim 1 wherein the step of producing an
asymmetrical tone burst includes producing a tone burst which is
asymmetrical in amplitude and asymmetrical in the relative duration
of the positive and negative portions of each complete cycle of the
tone burst signal.
5. The method according to claim 4 wherein the ratio of the
asymmetry of the amplitude of the first and second portions of the
tone burst is substantially 1:3 and the duration of the positive
and negative portions of each pulse of the tone burst also has a
ratio of 1:3.
6. The method according to claim 5 wherein the frequency of pulses
comprising the asymmetrical tone burst is approximately 1150 to
1450 times the repetition frequency.
7. The method according to claim 6 wherein the duration of the high
amplitude first portion of each tone burst is substantially
twenty-five percent of the total duration of the tone burst.
8. A transcranial electrostimulation apparatus including in
combination: a source of bipolar pulses of a first predetermined
frequency; source of modulating control signals to yield a second
frequency which is less than said first predetermined frequency; an
amplitude control means responsive to the modulating control
signals and coupled to the source of bipolar pulses at the first
predetermined frequency for causing the amplitude of bipolar pulses
in successive groups of bipolar pulses to vary in accordance with a
predetermined asymmetrical pattern at the second frequency.
9. A transcranial electrostimulation apparatus according to claim 8
further including a pulse shaper coupled with the source of bipolar
pulses of the first predetermined frequency to shape the dwell time
of the bipolar pulses of the first predetermined frequency.
10. The transcranial electrostimulation apparatus according to
claim 9 wherein the amplitude control means causes the bipolar
pulses to have a greater amplitude in a first portion of each group
of pulses and to have a lesser amplitude in a second portion of
each group of pulses.
11. The transcranial electrostimulation apparatus according to
claim 10 wherein the amplitude of the pulses in the first portion
of each group of pulses has an amplitude substantially three times
the amplitude of the pulses in the second portion.
12. A transcranial electrostimulation apparatus according to claim
11 including output electrodes coupled with the amplitude control
means.
13. A transcranial electrostimulation apparatus according to claim
11 wherein the source of modulating control signals is a frequency
divider coupled to the source of bipolar pulses of the first
predetermined frequency.
14. The transcranial electrostimulation apparatus according to
claim 8 wherein the amplitude control means causes the bipolar
pulses to have a greater amplitude in a first portion of each group
of pulses and to have a lesser amplitude in a second portion of
each group of pulses.
15. The transcranial electrostimulation apparatus according to
claim 14 wherein the amplitude of the pulses in the first portion
of each group of pulses has an amplitude substantially three times
the amplitude of the pulses in the second portion.
16. A transcranial electrostimulation apparatus according to claim
8 including output electrodes coupled with the amplitude control
means.
17. A transcranial electrostimulation apparatus according to claim
8 wherein the source of modulating control signals is a frequency
divider coupled to the source of bipolar pulses of the first
predetermined frequency.
Description
BACKGROUND
[0001] Bio-electric stimulation apparatus has been developed for
applying current pulses to a patient through electrodes located on
opposite sides of the head of the patient. The current pulses at
selected frequencies are applied to cause reaction with the central
nervous system of the patient. Such devices, referred to as
transcranial electrostimulation (TCES) or cranial
electrostimulators (CES) have been used for a variety of
noninvasive procedures, such as producing analgesic effects,
reducing or controlling migraine headaches, and other applications
of treatment and electro-anesthesia.
[0002] Earliest prototypes of transcranial electrostimulation
devices originated in Russia. These original designs, although
successfully employed for several different treatment modalities,
had a severe drawback with regard to the comfort of the wearer or
patient. In some cases, these earlier cranial electrostimulation
devices even subjected the wearer to pain. It has been discovered
that the reason for the discomfort of these earlier designs was a
result of the use of direct current as part of the overall
operation of the devices. The direct current was used to break down
or lower skin resistance to allow the treatment alternating current
signals to penetrate the brain and nervous systems to cause the
desired effect established by the placement of the electrodes on
the head of the patient.
[0003] In these earlier types of machines, the wearer received a
combination of direct current and alternating current electrical
waveform packages through a series of electrodes affixed to the
head with straps. Typically, two electrodes comprising a cathode or
negative pole of the DC based circuit would be placed approximately
three inches apart to the left and right of the center of the
forehead. Two other electrodes, comprising the anode of positive
pole of the DC based circuit, were placed on the rear of the skull
on the post mandibular area behind and below each ear.
[0004] With this DC current based design, the wearer was required
to place a thick pad between any electrode and the skin. Typically,
the pad was comprised of several layers of unbleached and uncolored
cotton flannel, or an equivalent product. For best results, the
fabric pads were soaked with water to provide a conductive path
between the electrodes and the skin of the wearer. Without the
presence of the pads (which were only required because of the
presence of the DC current), such devices could either burn the
skin of the wearer, or cause relatively intense pain before a
usable level of the treatment modality of the currents at the AC
frequency could be reached.
[0005] Although various types of treatment were employed by such
earlier transcranial electrostimulation devices, the devices
typically needed to be employed for an average time of thirty
minutes per treatment period. Without the presence of the
relatively thick cumbersome pads, the DC based design was unusable.
With the presence of the thick padding, the DC design was bearable
to the wearer, but rarely provided the wearer with a pleasant
experience.
[0006] Three Russian patents which utilize such devices for
different treatment methods comprise Russian patent Nos. 1489719;
1507404; and 1522500. In all of these patents, a combination of
direct current and rectangular impulse current, with a frequency of
between 70 and 80 Hertz, was employed at current amperages which
were increased from a relatively low level to a higher or maximum
level over the course of each treatment session.
[0007] An additional and potentially harmful drawback of the DC
based designs was that of iontophoresis. A characteristic of a DC
circuit application of this type is that molecular sized parts of
metal, toxins and other undesirable impurities can be caused to
migrate in the direction of current flow through the skin and into
the bloodstream of the wearer of such DC based CES devices.
Consequently, care had to be taken to ensure that no substance was
present other than water used to create good electrical contact
with the pad to the skin of the wearer. Since practically all CES
treatment modalities require repeated treatments, the potential for
iontophoresis being a harmful factor was escalated.
[0008] Transcranial electrostimulation (CES or TCES) originally was
used in the 1960's to induce sleep; These early devices typically
used less than 1.5 mA at 100 Hz. The Liss U.S. Pat. No. 4,627,438
employed higher frequencies modulated by a lower frequency
squarewave to produce recurring pulse bursts. The repetition
frequency of the device of Liss is determined by the modulation
frequency; but the pulse bursts are of a uniform amplitude within
each repetition cycle. The device of the Liss patent is
specifically directed to utilization in conjunction with the
treatment of migraine headaches. The low frequency or modulating
signal is asymmetrical, utilizing a 3:1 duty cycle, "on"
three-fourths of the time and "off" one fourth of the recurring
period. This results in bursts of the high frequency signal
separated by the off time when no signal is applied, following the
re-application of the bursts of the high frequency signal. Some
patient discomfort may be present in such an "on/off" system
operation over the period of time of application of the pulse
during a treatment interval.
[0009] A number of other United States patents, all directed to
dual frequency systems which utilize high frequency signals
modulated by a low frequency modulation carrier, operating in the
general nature of the device of the Liss U.S. Pat. No. 4,627,438,
exist. Typical of these patents are the patents to Limoge U.S. Pat.
No. 3,835,833; Nawracaj U.S. Pat. No. 4,071,033; Kastrubin U.S.
Pat. No. 4,140,133; Morawetz U.S. Pat. No. 4,922,908 and Giordani
U.S. Pat. No. 5,131,389. All of these patents employ a uniform
amplitude high frequency signal, which is modulated at the lower
frequency of the modulation carrier.
[0010] A variation on the systems of the patents discussed above is
disclosed in the Haimovich U.S. Pat. No. 5,540,736. The device of
this patent employs two different current generators for providing
electrical currents delivered to two electrode pairs operating
across different portions of the head of the patient. This allows
independent control of the current generators to administer
independent regulated electrical current across each of the pairs
to adjust for different impedances caused by the physiological and
anatomical differences between different sides of a patient's mid
brain portion, the quality of the conducting medium, and other
factors. In all other respects, the system disclosed in this patent
is similar to the operation of the system disclosed in the Liss
patent discussed above.
[0011] Russian patent publication No. 2139111 is directed to a
method for treating narcomania, which is a treatment also used in
others of the CES patents described above for alcohol and narcotic
addiction. In this patent, transcranial electrical stimulation is
accomplished by means of packets of current with a duration of four
milliseconds, at a modulation frequency of 100 Hz. Within each of
the packets, the high frequency signals have a uniform frequency
and current amplitude.
[0012] It is desirable to provide a transcranial electrostimulation
apparatus and method which overcomes the disadvantages of the prior
art, and which has increased effectiveness and increased user
comfort.
SUMMARY OF THE INVENTION
[0013] It is an object of this invention to provide an improved
transcranial electrostimulation apparatus and method.
[0014] It is an additional object of this invention to provide an
improved transcranial electrostimulation apparatus and method which
does not employ direct current components.
[0015] It is another object of this invention to provide an
improved transcranial electrostimulation apparatus and method
employing only alternating current components.
[0016] It is a further object of this invention to provide an
improved transcranial electrostimulation apparatus and method
utilizing packets or groups of high frequency pulses which vary
amplitude within each of the packets in a uniform manner and in
which the packets are repeated at a lower modulation frequency for
application to electrodes for effecting transcranial
electrostimulation.
[0017] In accordance with a preferred embodiment of the invention,
a transcranial electrostimulation apparatus includes a first
generator of bipolar pulses at a first predetermined frequency. A
source of modulating control signals at a second frequency, which
is less than the first predetermined frequency, is employed in
conjunction with an amplitude control circuit receiving the pulses
of the first predetermined frequency to produce bipolar pulses at
the first predetermined frequency, which vary in amplitude in an
asymmetrical pattern at the frequency of the modulating control
signals.
BRIEF DESCRIPTION OF THE DRAWING
[0018] FIG. 1 is a diagrammatic drawing illustrating the overall
principles of operation of the system in accordance with a
preferred embodiment of the invention;
[0019] FIG. 2 is a waveform of a typical signal pattern of a
preferred embodiment of the invention; and
[0020] FIG. 3 is a block diagram of a system for producing the
signals shown in FIG. 2.
DETAILED DESCRIPTION
[0021] Reference now should be made to the drawings which
illustrate a preferred embodiment of the invention and its
operation. FIG. 1 is a diagrammatic representation of the salient
operating features of circuitry implementations which produce a
unique triple waveform asymmetry useful for various transcranial
electrostimulation applications. The unique waveform which is
described in detail in conjunction with FIG. 2 produces little to
no discomfort to the user of the device.
[0022] As illustrated in FIG. 1, the basic high frequency current
signals are produced by a high frequency generator 10, which may
employ a frequency control 12 and a pulse duration control 14 to
establish the basic frequency and to provide the desired asymmetry
between the positive and negative portions of each of the pulses
produced by the generator 10. Typically, the generator 10 may
include a crystal oscillator operating at 1,000 to 1,200 kHz, which
then is divided down to the desired operating frequency of the
alternating current pulses applied to the transcranial stimulation
electrodes. Typically, the division ratio may be a 1:4 ratio to
produce signals which then are modulated by a low frequency
generator 16.
[0023] As illustrated in the diagrammatic representation of FIG. 1,
the output of the low frequency generator 16 may be established by
means of a conventional frequency control 18, a pulse duration
control 20, and a modulation depth control 22 to produce a
composite modulated output signal at 24, which comprises the pulses
from the output of the high frequency generator 10 modulated by the
low frequency generator 16. The output 24 then is provided with an
amplitude control 26 to establish the amplitude of the pulse train
supplied through the system to a power amplifier 28. The current at
the power amplifier 28 may be varied in accordance with the
treatment modality to be used by the system; and this current is
measured by an ammeter 34. The power amplifier 28 then supplies
appropriate transcranial alternating current pulses to a pair, or
multiple pairs, of electrode outputs, illustrated as a single pair
30 and 32 in FIG. 1.
[0024] The operation of a preferred embodiment of the invention,
for producing a waveform having triple asymmetry in order to
produce effective transcranial electrostimulation, now should be
considered in conjunction with the waveform of FIG. 2 and the block
diagram of the system shown in FIG. 3. The block diagram of the
system shown in FIG. 3 is typical of a manner of implementation of
the various circuit functions required to produce the waveform of
FIG. 2; but other arrangements for producing the signal waveform
also may be utilized. In FIG. 3, a crystal oscillator 50 is
employed to provide the basic alternating current operating signals
utilized for both the high frequency pulses and the modulating
pulses illustrated in FIG. 1 as being produced by the high
frequency generator 10 and the low frequency generator 16.
Typically, the oscillator 50 may have an operating frequency in the
order of 1,000 kHz to 1,200 kHz (although other frequencies may be
used). The output of this oscillator is supplied to a divider 52,
which may comprise multiple division stages, to produce the lower
modulating frequency (illustrated in FIG. 1 as being generated by
the low frequency generator 16). The output signals from the
oscillator 50 also are supplied through a divider 54 to produce the
operating signal waveform shown as the squarewave signal in the
waveform of FIG. 2, after being shaped by a pulse shaper 56, to
achieve the generally squarewave configuration of FIG. 2. In the
example given, these pulses occur at an alternating current rate of
100 KHz; although they could be at higher or lower frequencies in
accordance with particular applications of the system.
[0025] The pulses from the output of the divider 54 also are
supplied to a counter 60, which may be of any suitable type such as
a cascade counter or a ring counter, for producing outputs on leads
64 and 66 utilized in controlling the amplitude of the pulses from
the pulse shaper 56. The counter 60 is reset by the output of the
divider 52, applied over the lead 62, to reset the counter for each
cycle of operation of the divider 52. In the present example, the
output of the divider 52 (comprising the low frequency modulation
control signal) is selected to be 77.5 Hz, since this repetition
frequency has been found to be highly effective in conjunction with
transcranial electrostimulation devices. Repetitive frequencies
which are in the range of 70 Hz to 85 Hz have been found to be
effective, but a frequency of 77.5 Hz has been empirically
ascertained as a general ideal operating frequency for producing
the maximum efficacy of the system.
[0026] The modulating or reset frequency, applied over the lead 62,
could as well be supplied by a second independent crystal
oscillator, operating at a lower initial frequency than the
oscillator 50, if desired. If two different signal sources are
employed, synchronization between the two should be effected to
cause the various pulse transitions of the signals to be correlated
with one another in order to produce the signal waveform of FIG. 2.
The system shown in FIG. 3, however, is one effective way of
accomplishing this.
[0027] Assume, for the present example, that the counter 60 has
been reset to its initial or "zero" count. The system then operates
to supply output pulses at the high frequency of the divided down
signal from the divider 54 to the counter input, which advances one
count for each of the applied pulses. In the waveform shown in FIG.
2, the initial pulses (the first four in FIG. 2) cause the counter
outputs on 64 and 66 to be such that, as these outputs are applied
to the amplitude control 68, a maximum amplitude (which may be
adjusted if desired) is produced. This is illustrated in the
left-hand portion of the waveform signal of FIG. 2. When pulse No.
4 in the group or packet is applied, a signal is obtained from one
or both of the outputs 64 and 66 of the counter 60 and applied to
the amplitude control circuit 68 to switch it to a lower amplitude,
as illustrated for the right-hand portion of the signal shown in
FIG. 2.
[0028] This causes the output of the amplitude control circuit 68
as applied to a regulator amplifier 58, to produce the signal
waveforms in the asymmetrical pattern shown in FIG. 2, wherein the
left-hand one-fourth (42) of each of the signal bursts is at a high
amplitude; and the right-hand portion (44) comprising the remainder
of the pulses is at a lower amplitude. The ratio is such that
one-fourth (the initial amplitude) is at the high amplitude range,
and that the remainder three-fourths is at the low amplitude range.
This is the first level of asymmetry of the applied signals.
[0029] The regulator amplifier 58 also operates on the squarewave
shaped pulses from the pulse shaper 56 to cause a second asymmetry
in the positive and negative going aspects of the signal. As shown
in FIG. 2, the negative going amplitude is one-fourth of the total
excursion of the signal; and the positive going portion is
three-fourths of the total excursion. This is true of both the
maximum amplitude pulse 42 burst at the beginning of each of the
burst groups or packets, and the lower amplitude portion 44 at the
end of each of the burst groups or packets.
[0030] Finally, the third asymmetry is produced within the thirteen
milisecond squarewave burst envelope illustrated as 40 in FIG. 2.
This is the result of the operation of the divider signal on the
lead 62 comprising the reset operation for the counter 60. The
composite asymmetrical signal illustrated in FIG. 2 then is
provided by the output of the regular amplifier 58 to a power
amplifier 70. The amplification may be adjusted to change the
amount of current applied by the system (while maintaining the
relative waveform shapes and patterns shown in FIG. 2) in
accordance with the treatment modality to be utilized by users of
the system. The ammeter 74 is employed to measure the magnitude of
the current supplied by the system. It may be a simple analog
ammeter, or it may be a digital ammeter providing separate readings
of the maximum amplitude and minimum amplitude portions of the
signal which is shown in FIG. 2.
[0031] The output of the amplifier 70 may be applied through a
polarity switch 72 which allows the polarity of the signals applied
to the spaced electrodes to be reversed, if desired. The polarity
switch 72 supplies the signals across a pair of spaced output
electrodes 76 and 78 which may in the form of pairs of split anodes
and split cathodes, or which may be a single "anode" and "cathode"
pair. Since no direct current components are present, the electrode
paths connected to the outputs 76 and 78 are not really anodes and
cathodes; but, depending upon the treatment which is being
effected, it may be desirable to apply the positive going portions
of the pulses to one or the other of these electrodes and the
negative going portions to the other to achieve specific
results.
[0032] It should be noted that in the system which is shown and
described, there are no direct current components. It also should
be noted that although the system essentially is illustrating 70
kHz to 120 kHz tone bursts in each of the burst envelopes 40 shown
in FIG. 2, other frequencies could be employed. As noted, the 77.5
Hz waveform, derived through the timing cycle, is used to complete
each burst envelope including first pulses of a relatively high
amplitude, followed by a series of pulses of a relatively low
amplitude, in accordance with the signal pattern shown in FIG.
2.
[0033] In the system which is disclosed, an individual squarewave
pulse of 0.01 Ms is utilized with 0.0075 Ms in the negative portion
of the pulse and 0.0025 Ms in the positive portion of each of the
pulses. The general asymmetrical waveform which is described above
in conjunction with FIG. 2 has been found to be effective when it
is centered around three-to-one ratios throughout the system
operation. These ratios of course may be varied, in accordance with
corresponding variations of other ratios of the system; but it has
been found that the asymmetrical relationship which is disclosed
replaces the formerly necessary, but unpleasant, DC portion of the
operating protocol of earlier systems.
[0034] The DC current employed in some of the prior art devices was
designed to provide a path penetrating the natural capacitive
resistance of human skin. The DC current reduced the resistance to
approximately 300 to 400 Ohms. The cost, however, was a high level
of discomfort for the user of the device. It has been found that
the utilization of the unique asymmetrical signal produced by the
system shown in FIG. 3 and illustrated in the waveform of FIG. 2
effectively lowers the capacitive resistance of the epidermal layer
to something on the order of 100 Ohms. Since less resistance is
presented to the integrated 77.5 Hz modulating frequency, lower
current levels are capable of achieving the same desired result
which previously required much higher current levels. The lower
current levels translate into a greater level of comfort for the
patient or user of the device.
[0035] The foregoing description of the preferred embodiment of the
invention is to be considered as illustrative and not as limiting.
Various changes and modifications will occur to those skilled in
the art for performing substantially the same function, in
substantially the same way, to achieve substantially the same
result without departing from the true scope of the invention as
defined in the appended claims.
* * * * *